1. Field of the Invention
This application relates to frame interpolation in digital video. In particular, this application relates to systems and methods for determining motion vectors for motion compensated interpolation.
2. Description of the Related Technology
In recent years, advancements in digital video processing have allowed video display manufacturers to produce systems which provide a more realistic viewing experience by enhancing raw digital video. For example, one way of enhancing video materials is to increase the displayed frame rate by generating and displaying frames that are interpolated based on the content of previous and/or succeeding frames. For example, filmed video from sources such as motion pictures typically includes 24 frames per second (fps). Video devices often have refresh or display rates of 50 or 60 frames per second. One well known way to render 24 fps video at 60 fps is to repeat every 4th frame in a 2-3 pattern for progressive video or a 3:2 pulldown process that repeats fields of frames in a 3:2 pattern to produce an interlaced 60 fps video signal. In either case, the 3:2 pattern can result in jerky or jittery video that is particularly apparent during slow, steady camera movements. This artifact is commonly referred to as telecine judder. A way of enhancing display of 24 fps video is to interpolate frames to reach 60 fps rather than simply repeating frames to reduce or eliminate such judder. In addition, display or other video processing devices may utilize frame interpolation in other frame rate conversion applications or to interpolate frames of a video signal lost to signal or other noise.